Electricity that is, for example, generated in high-sea wind parks has to be transported to the consumer with minimum losses. Here, in addition to high-voltage direct current transmission, cables consisting of supra-conducting material offer a promising alternative. Supra-conductors enable direct current transmission without losses.
Metal bands coated with a supra-conducting material and covered with a protective layer of copper are often used to make supra-conducting cables. A cable then consists of stacked bands that are soldered to one another and encased in a copper cover. However, the supra-conducting bands are usually not longer than 100 metres. In order to use them for kilometre-long power cables, several cable sections have to be connected to one another.
The method commonly used nowadays to connect the cable sections consists of baring the supra-conducting cables at their ends and then soldering them to one another individually. However, this process is very time and cost intensive and is unsuitable for applications on an industrial scale. As an alternative, a connecting section made of copper is used into which the cable sections are laid from both sides so that they overlap. The disadvantage of this is the relatively large space required and the high resistance of the copper.
KIT scientists at the Institute for Technical Physics (ITEP) have developed a connector that consists of a copper body with recesses for the cables. Bands of supra-conducting material run along these recesses. The cables that are to be connected are closely aligned with the supra-conductor bands, enabling power transmission from one section to the next virtually without any losses. In order to fixate the connection, a liquid metal alloy is used as solder, and the connector is closed with a lid. The compact copper body can designed in a manner enabling it to link cables either in a straight line or at an angle.